Blue glowing giant lightning energy field in space, computer generated abstract background, 3D rendering


Blue glowing giant lightning energy field in space, computer generated abstract background, 3D rendering

Photo by: sakkmesterke


Why We Know Nothing about Dark Matter and Dark Energy

Welcome to the era of precision cosmology…where we’ve managed to very precisely measure everything we don't know about the universe.

Cosmology is the study of the universe. As in, the whole entire universe as a single physical object. Cosmologists try to understand the origins, history, evolution, contents, and ultimate fate of this place that we call our home.

Modern cosmology got its start about a hundred years ago when astronomer Edwin Hubble discovered two remarkable things: that galaxies exist and are very far away from us, and that those galaxies are receding away from us. In other words, he discovered that the universe is very large and that it’s expanding.

Modern cosmology rests on the big bang theory, which states that a long time ago, our universe was smaller, hotter, and denser than it is today. We have tons of evidence to back up this very simple statement, but that doesn’t mean we understand everything we wish we could about how the universe works.

In fact, there are two glaring holes in our understanding. One is called dark matter, which was discovered in the 1970s. As far as we can tell, dark matter is made of some new kind of particle with a mysterious identity and properties. Dark matter does not interact with light or with normal matter, but it does take up the vast majority of all the mass in the universe.

The other giant hole is called dark energy. In the late 1990s two teams of astronomers discovered that the expansion of the universe is accelerating. Not only is our cosmos getting bigger and bigger every day, but it’s also getting bigger and bigger faster and faster every day. We have absolutely no idea what’s going on, so we named the effect dark energy.

To account for the accelerated expansion, dark energy takes up almost 70% of all the mass energy in the entire cosmos, completely dominating everything else, including dark matter. So modern cosmology is in kind of a weird place.

We understand the general picture of the big bang, and we’re able to confidently make some really cool statements, like the age of the universe is 13.77 billion years old, or that all the hydrogen atoms were formed when the cosmos was only a dozen minutes old. We can back up all those cool statements with plenty of evidence, so we know we’re on solid ground. But we still lack an understanding of the vast majority of the contents of our universe.

We know how they behave, but not what they are. So the name of the game in modern cosmology is to keep measuring the properties of dark matter and dark energy as precisely as possible, and hope that something interesting pops up. The latest result comes from the PANTHEON+ survey (and no, that’s not a new streaming service), which measured the precise positions of about 1,500 supernovae.

Using the data, the team behind the study found that our universe is 66.2 percent dark energy, and 33.8 percent dark matter and normal matter (with most of that being dark matter). Unfortunately, PANTHEON+ didn’t discover any surprises when it came to those twin mysteries, so we’re just going to have to keep digging.

Next Up

Why Astronomers Care About Super-Old Galaxies?

A long time ago, our universe was dark.It was just 380,000 years after the big bang. Up until that age, our entire observable cosmos was less than a millionth of its present size. All the material in the universe was compressed into that tiny volume, forcing it to heat up and become a plasma. But as the universe expanded and cooled, eventually the plasma changed into a neutral gas as the first atoms formed.

What We’ve Already Learned From James Webb? (Hint: it’s a lot)

That was worth the wait. Just a quick handful of months since its historic launch on Christmas Day, the James Webb Space Telescope has flown to its observing position, unfolded its delicate instruments and ultra-sized mirror, and run through a suite of checks and alignments and calibrations. The team at NASA behind the telescopes released their first batch of images from the science runs, and besides being gorgeous, they're powerful.

A Guide to this August’s Best Astronomy Attractions

Learn more about the exciting things happening in the night sky this month! From the rings of Saturn to the most popular meteor shower of the year, August 2022 has us stargazing all month.

How Astronomers Use a Trick of Gravity to See the Most Distant Objects in the Universe

Let’s say you’re an astronomer (work with me here) and you want to take a picture of something incredibly, deeply far away. You know, the typical business of astronomy.

South Korea Joins Space Race by Sending its First Spacecraft to the Moon

South Korea is launching its first lunar probe to the moon on August 4th. The Korea Pathfinder Lunar Orbiter (KPLO) or Danuri, developed by the Korea Aerospace Research Institute (KARI) is being launched to study moon carters, magnetic fields, and surface weathering.

How Exoplanets Became the Next Big Thing in Astronomy

To date, we know of over 5,000 planets outside the solar system. And astronomers suspect that there may be *checks notes* around a trillion more in our galaxy alone. The search for exoplanets is one of the hottest topics in astronomy, with expensive telescopes and giant collaborations all searching for the holy grail of the 21st century: an Earth 2.0, a habitable world like our own.

Jupiter Makes Its Closest Approach to Earth in Nearly 60 Years

The last time Jupiter appeared this large and bright in the sky was in October 1963.

6 Months in Space Permanently Ages Bones by 10 Years

Astronauts on long-term space missions can experience bone loss equivalent to two decades of aging. New research suggests more weight-bearing exercises in space could help offset that decline.

The Perseid Meteor Shower Reaches its Peak

Stargazers rejoice! The annual Perseid meteor shower is upon us. Here's what you need to know...(updated August 11, 2022)

Got You! Astronomers Find an Especially Sneaky Black Hole

Black holes are tricky creatures. Since ancient times the practice of astronomy has been to point our eyes and instruments at all the glowing things in the skies above us. But black holes are defined by the fact that nothing, not even light, can escape their gravitational clutches. So how you do see something that is completely, totally black?

Related To: